Mazen Malek Shiaa

An Incremental Graph-based Approach to Automatic Service Composition

In the Service Oriented Architecture paradigm services are self-contained software units of functionality. Several services can be composed to assemble a composite service that provides an overall functionality. This process is called Service Composition. The automation of the service composition process aims at decreasing the human intervention during the service discovery, matching, ranking, filtering and reasoning about the resulting composition candidates. The paper presents an innovative approach to automatic service composition. The discovery and matchmaking is based on semantic annotations of service properties, e.g. their inputs, outputs and goals. The approach uses a graph-based search algorithm to determine all possible composition candidates and applies certain measures to rank them. Filtering and reasoning is accomplished by validating the composition candidates using goal-based expressions.

Mobility support framework in adaptable service architecture

Mobility is regarded as the most important feature needed to achieve adaptability and flexibility in the execution of service components. As such, service systems could be able to cope with the handling of dynamic changes in the availability of resources and position of users. On the other hand, providing user-centric and personal-content driven wide range of services, more commonly wireless ones, to end users regardless of their location and used equipment, seem to be the most important objective of such a feature. Mobility, in this context, is a feature facilitating the free and coordinated movement of, for instance, users, software components, user terminals, etc. One should always consider the vibrant configuration and settings of not only end-users applications and environment, but also the network resources, components and services. The reason is due to the ever changing and increasing demands and requirements in functionality, security, reliability and QoS. Mobility support in self-managing, dynamically configurable network architecture seems to be even more challenging, however recent development and improvements in network infrastructure show a greater prospect for code-on-demand and adaptive network management. TAPAS, and its mobility handling architecture, presented in this paper, tend to give some answers and take a step towards achieving such goals.

A dynamic configuration architecture

Network-based services have, for more than a decade been, been an important research topic. A demand has arisen for a platform with functionalities beyond existing solutions. The paper develops a formal framework for dynamic configuration and reconfiguration of services in TAPAS - telematics architecture for plug-and-play systems (see http://tapas.item.ntnu.no). It provides representation, computation and reasoning mechanisms for semantic description and matching of required and offered capabilities and status which are required by a particular service system. It employs CIM and recently developed languages for the semantic Web in order to provide a mechanism for human-readable and machine-comprehensible descriptions of status, capabilities, system (re)configuration plans as well as exchanging messages. It also exploits XML declarative description (XDD) theory to unify such various languages seamlessly into a single uniform formalism. It permits formal definitions of application-specific configuration requirements and constraints as well as reconfiguration policies. Reasoning about these definitions and the available capabilities/status of nodes in the system yields appropriate (re)configuration plans for the composition of new services and for adaptation of current services.

Architectural Considerations for Personal Mobility in the Wireless Internet

Personal Mobility, and the need for it, is considered to be the main driving force behind the spreading of the Wireless Internet. Moreover wireless devices and applications are being developed based on a basic assumption that users need to get access to services regardless of their location and used equipment. Wireless Services, on the other hand, are very dynamic and have a vibrant configuration and settings. In order for this to be utilizable a new network architecture is required. In our department we are developing Telecommunication Architecture for Plug-And-play Systems (TAPAS) to be a generic platform and application development environment based on plug-and-play technology, which uses the Web as means for service definition, update and discovery. TAPAS is intended to satisfy three basic classes of properties: Flexible and adaptable, Robust and survivable, and QoS aware. Personal mobility falls into the first class. Aspects of user, application and session mobility are dealt with using different mobility management schemes. The paper discusses trends in the Wireless Internet concerning devices, applications and services, and presents the approach used within TAPAS. Personal mobility, in this context is based on the user, terminal and session mobility.

An XML-Based Framework for Dynamic Service Management

Service systems are likely to be highly dynamic in terms of changing resources and configurations. On the one hand, resources are increasingly configurable, extendable, and replaceable. On the other hand, their availability is also varying. For this reason, the handling of these changes is crucial to achieve efficiency. To accomplish this objective, a framework for dynamic service management with respect to service specification and adaptation is proposed.

Mobile Ontology: Its Creation and Its Usage

This paper is a summary on experiences gained and lessons learned from applying semantic technology in EU IST SPICE project. The paper describes the motivation of using ontology in the project, the ontology itself, the usage of the ontology inside and outside the project, and the challenges we met during the whole course.

Validation Aspects of Automatic Service Composition

The paper studies the validation aspects of service composition, in particular the goal-based aspects. By service composition we are targeting the automated composition of service components that fit certain demands from a portfolio of available service components --- typically referred to as service repository. It is arguable that the use of ontologies and semantic annotations of service components constitute an intelligent way to enhance service discovery and service composition mechanisms. However, validating the intention of a certain composition --- goals --- and verifying its requirements is still a topic for research development. This paper presents a simple approach to validate service compositions based on goal annotations. The effectiveness of this approach is highlighted through a simplified service example.